1. Field of the Invention
The present invention relates to an actuator with a sensor for obtaining information on distance from or contact state with an object.
2. Description of the Related Art
In order to improve the controllability of an actuator, it is important to detect information on distance from or contact state with an object. Thus, a method of forming a sensor such as a tactile sensor on the side of an actuator facing an object has heretofore been adopted.
As an example where a polymer actuator is combined with a sensor, such a construction that electrodes are formed directly on an actuator has been known as disclosed in Japanese Patent Application Laid-Open No. 2006-129541. In Japanese Patent Application Laid-Open No. 2006-129541, two or more electrodes are arranged on a filmy surface of a conductive polymer actuator exhibiting a stretching action to detect a resistance value between the electrodes. This utilizes a phenomenon that the conductivity of a conductive polymer varies according to quantity of stretching and is an internal sensor for detecting driven quantity of the actuator. On the other hand, since the conductivity varies even in a case where displacement such as strain or bending is given to the actuator by contact with an object, it can be utilized as a sensor.